Powerheads disturbing sandbed

cobra2326

New member
First, I want to say thank you to WaterKeeper and all the others who have taken much time to inform us newbies about reefkeeping. You've saved me lots of trouble already.

Second, I'm Jon and this is my first post.

I have a 55, DSB w/ about 31 lbs of live rock (just to start off). It was fully cured when I bought it from the LFS, so ammonia has been at zero. I recently bought 2 Maxi-Jet 1200's for water movement and they're creating a problem with my DSB. I can see the very top layer being disturbed by the water turbulence. Any ideas how to fix this?

The two powerheads are at the upper back corners of the tank, in an X pattern, pointed horizontally.

Thanks in advance.
 

sufunk

New member
Welcome!

Try pointing one of them towards the surface. This will give you some surface agitation which is good and hopefully will stop any sandstorms while still giving you good flow.
 

cobra2326

New member
Tried that, one pointing up and the other pointing horizontal. Apparently, when on opposite sides of the tank, they eventually intersect and create turbulence, which stirs the sand bed. It doesn't create a sandstorm, but you can see the sand being lifted up and kicked around. For now, I've disabled one so as to not disturb the bed. Hopefully others can interject.
 

bertoni

Premium Member
[welcome]

In tanks with high flow, some sand disturbance is inevitable. Some aquarists choose not to use sand for this reason. You could see whether the tank reaches an acceptable stable point.
 

cobra2326

New member
Thanks bertoni. I'll try to allow the bacteria in the sand to seed better before I run both pumps again. Considering the live rock was seeded and I've seen no trace of ammonia, I'll probably need something to load the tank and allow the bacteria to populate.
 

reefnetworth

Premium Member
a pinch of fish food will start a nitrogen cycle. add just 2 or 4 flakes without any carbon for about 2 days and youll see a slight change in parameters. do a 10%-25% water change just like you would if it were uncured rock.
as far as the PH situation, my suggestion is: one at each end of the tank facing each other so the flow hits/collides in the middle. it will cause a wave like effect if when you get it right on the $$$.
 

AZDesertRat

In Memoriam
Newer powerheads like Hydor Koralias, Rio Seios or Tunze NanoStreams may be better choices than Maxi Jets. They all move much more water but in a nice spread out or diffused pattern so its not like a jet or concentrated stream. 2 of these with the diffused flow do not crash against each other so violently and disturb the sand bed so bad.
They are also much more efficient only drawing about 13 watts and moving 1200 GPH in the case of the Koralias, much less than the 23 watts of the MJ 1200 at only 292 GPH. I can say my corals and fish both love them.
You are correct in that once the bacteria colonizes better the sand becomes heavier and stays put much better. Even when it gets disturbed it drops like a rock.
And welcome to RC !!!
 

reefnetworth

Premium Member
if you wish to buy more PHs that may be a different situation. but to take care of the immediate problem try my suggestion and then decide what you like.
i also forgot to mention to place them (PHs) about 4" or so, under the surface to release CO2 and induce oxygen to help in stabilization of pH somewhere between 7.8 - 8.5 with 8.2 being reef and 8.3 being mainly fish. :D
 

reefnetworth

Premium Member
the variance of 7.8 - 8.5 is found in Natural Sea Water (NSW) environments worldwide... they're the minimum and maximum before damage begins. :D
 

kuoka

Premium Member
I use seios and had the problem too. It took me about a week of repositioning to get it to stop. The challenge is the flow hits the front of the tank and travels downward to the sand. You might want to try positioning them on the sides of the tank and upwards agitating the water won't hurt either.
 

serum153

New member
The reason is that the 55 is too narrow, so having them on the back pointing to the front glass is about 10 inches and that is why you are having the problem. I have my 2 mj1200's on opposite sides of the tank, but one higher than the other pointing up towards the surface. I run my hydor koralia very low on the side of the tank and I haven't disturbed the sandbed what so ever. Trial and error...be sure to watch the flow of your fish food when you feed and adjust as needed to correct any dead spots.
 

cobra2326

New member
Thanks guys, these posts have really helped. For now, I'm FOWLRALS :), so I think one powerhead will do until I get a fully established cycle.
 

cobra2326

New member
Thanks guys, these posts have really helped. For now, I'm FOWLRALS :), so I think one powerhead will do until I get a fully established cycle.

Serum, how do you like your AragAlive sand? I have 50lbs of home depot silica sand topped with 40lbs of AragAlive, but I haven't noticed any life in the sand yet. I'm thinking about getting a detrivore kit, kinda sad considering its $25 for a 20lb bag of the Arag.
 

INCEPTION7

New member
Cobra,

I differ in opinion with the other posters. First of all how deep is your sand bed? Second, try mounting the MJ's on the front corners, then point them in and up so they intersect above the rock and not the sand. The point of a DSB is the growth in the lower portions of the sand bed. If you say only the very top of the bed is being disturbed, then the portion where the "action" takes place is not being bothered. Can I ask you why you chose a DSB instead of a bed less then 1"?
 

Aquarist007

New member
also putting them on a wave timed receptacle will give you alot of variance and turbulance.

Inception7---I was advised when I first got my reef tank to go with the less then one inch substrate. Lately I am questioning that wisdom----to increasing the sand bed to get take advantage of anerobic bacteria-----i need the realestate for fish now so adding more rock would take up much more space then increasing the substrate
 

Aquarist007

New member
I personally like a power head directed at the bottom--it helps keep that area free of unused food, phosphates etc etc. If blowing sand becomes an issue had some rock rubble around the problem area and it will help keep the sand in place plus increase the biological filtration in the overall system(slightly but it is bonus in this situation)
 

INCEPTION7

New member
Capn,

There are two schools of thought here. 1) less then 1" of substrate (ooltic or other fine) will hinder the substrate from becoming a nitrate trap. 2) A substrate of more then 3" will have a denitrifying effect. The only thing about having a DSB is it must be maintained. I do not use a DSB in any of my tanks because of this. If the bed is not maintained (stirred lightly, replenished top layer every 6-8 months) it can cause a reverse effect and possibly crash the system. To me, the best things you can do to keep nitrates at 0 are keeping up with regular water changes, feed lightly, change filter media weekley and have a refugium that totals AT LEAST 10-20% of total water volume filled with macroalgae such as Chaeto that won't go sexual.
 

cobra2326

New member
<a href=showthread.php?s=&postid=10425464#post10425464 target=_blank>Originally posted</a> by INCEPTION7
Cobra,

I differ in opinion with the other posters. First of all how deep is your sand bed? Second, try mounting the MJ's on the front corners, then point them in and up so they intersect above the rock and not the sand. The point of a DSB is the growth in the lower portions of the sand bed. If you say only the very top of the bed is being disturbed, then the portion where the "action" takes place is not being bothered. Can I ask you why you chose a DSB instead of a bed less then 1"?

My sand bed is about 4". I'm using 50lbs of crap fine silicate for the bottom layer and 40lbs of AragAlive bahamas oolite for the top layer.

The problem with the top layer being disturbed is that it slowly 'erodes' away to the lower layer. I watched this happen last night.

As for the DSB: I chose a DSB based on the idea that it can, eventually, provide a region for active denitrification in the tank. I realize it's not the only way to accomplish it. To me, a SSB provides plenty of detoxifying properties, but in the end, it seemed almost equivelent to a canister, i.e. produces nitrates but does little in the way of removing them from the tank.
 

INCEPTION7

New member
Yes, I have tried DSB's and saw little to no benifit. Maybe I have been lucky but I have never had any problems with Nitrates in any of my tanks. I think it all comes down to feeding carefully, changing water and filter media and having a good skimmer. To each his own though, good luck with the dsb. I personally would suck all that sand up and invest in a reverse lighted refugium with chaeto.
 

cobra2326

New member
Well, it's pretty clear that there is no one right way to do this. Obviously, your nitrate levels speak for themselves. Additionally, I'm a total newb with a crappy skimmer, so I need all the help I can get. Eventually when I get a fuge, the SB may prove less important.

I always appreciate differing views and advice instead of the same old checklist.
 
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